Recently, there has been increasing evidence that the anion transport is responsible for many if not all of the epithelial manifestations of CF. The research in this project is aimed at determining the nature of the defect of anion transport using cells in tissue culture. The specific aims of the proposed studies are the following: 1) To characterize the anion transport in erythrocytes and in cell cultures of fibroblasts and epithelial cells derived from normal individuals and patients with cystic fibrosis. Classic radioactive tracer methods as well as newer electron probe methods we have developed will be used to measure anion transport in fibroblasts and epthelial cells in culture. Known anion transport inhibitors will be tested for specific binding to the defective anion transport proteins in cystic fibrosis. 2) To characterize the anion channel proteins, we will compare the normal and CF derived proteins by two-dimensional gel electrophoresis and protein chemistry techniques. 3) To study the DNA structure coding for the anion channel we will build on studies already underway to elucidate the sequence in the anion exchange channel (Band 3 protein) in the erythrocyte. Once the DNA sequence for the anion channel has been established we will attempt to test for homology between the erythrocyte derived DNA and RNA derived from fibroblasts and epithelial cells using northern blotting techniques. If there is no significant homology between the red blood cell anion exchange channel DNA and the RNA coding for the fibroblasts and epithelial cell anion transport proteins, we will attempt to use specific anion channel inhibitors, to label the channel and begin the amino acid sequence characterization. The overall goal will be the isolation and characterization of normal and CF anion transport genes. The findings of these studies would be very important in leading to a more basic understanding of Cystic Fibrosis.